Chimney cover apparatus
BACKGROUND OF THE INVENTION 
     The covering of chimneys associated with dwellings is important in preventing water and snow from entering the chimney flue and causing damage as well as preventing small animals and birds from gaining access to the dwelling via the chimney flue. Generally chimney covers are employed to provide shelter to keep rain and snow out of a chimney flue. Often the means provided for fitting the conventional cover can be dislodged by animals such as raccoons, to gain entrance to a house for food or shelter, and once in, cause much damage to the contents of the dwelling. Often chimney covers are attached with screws and require holes to be drilled in the ceramic chimney flue with substantial risk of cracking and damage to the flue. 
     Chimney covers or alternatively chimney caps of which applicant is aware are shown in U.S. Pat. Nos. 4,436, 021, 4,534, 280, 832,1 888, 1,490,186, 2,805,616, 4,549,473 and 4,487,112. 
     It is desirable however to provide for an improved, simple, yet effective chimney cover to provide for the improved attachment to the chimney with the combined feature of preventing entry by animals while emitting smoke and provide for adjustment of the roof of the cover with respect to the chimney to improve the flue draft and prevent down drafts resulting in smoke entering the house rather than exiting the fireplace via the chimney flue. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved chimney cover, a chimney cover system employing the improved chimney cover and a method of controlling the flow of smoke employing the improved chimney cover of the invention. 
     The present invention comprises an improved chimney cover which includes an adjustably mounted roof mounted over a dome-shaped screen, attached to a mounting band having a discontinuity, adapted to be positioned on the top of a chimney flue, and to prevent entrance thereto by small animals or birds. The chimney cover is provided with a plurality of paired support arms to adjustably support the roof in relation to the top of the chimney flue. The mounting band is typically of metallic construction is generally rectangular in shape, and is provided with a discontinuity on each side comprising a right hand and a left hand slide bar each having elongated slots for engaging rivet fasteners. The wire mesh attached at a plurality of points to the metallic band, is formed with a dome shape to prevent settling of debris on it&#39;s center or axis portion and to provide natural resilience serving to produce an outward tension on the mounting band and prongs mounted thereon to fit a plurality of chimney flue sizes. 
     The mounting band comprises a plurality of prongs, preferably metallic in the preferred embodiment, with an inverted J shape, oriented outward naturally and capable of contacting the interior as well as exterior wall of a chimney flue to secure and immobilize the present invention therein. 
     The user of the chimney cover may select the desired height of the roof relative to the chimney flue depending on the prevailing wind drafts to improve the updraft in the flue to better evacuate smoke from the fireplace provided in communication with the chimney flue. Alternatively for periods of nonuse, the roof may be lowered to completely enclose the top of the flue. 
     As also contemplated by the invention, the improved chimney cap may be employed to provide protection as a spark arrester to reduce the risk of fire by the action of the wire mesh and by controlling the air flow of the updraft to reduce the build up of creosote on the inner surfaces of the chimney flue. In addition the folding feature of the adjustable support arms permits compressing the present invention to a compact form for ease of packaging. 
     The chimney cover of the invention may be employed in a chimney cover system whereby the amount of down draft of air from outside the chimney and smoke laden updraft air rising upwardly from a fireplace connected to the chimney flue is controlled by adjusting the height of the roof of the present invention and hereby changing the size of the opening provided by the chimney cover. 
     The invention also includes a method for the controlled flow of smoke laden air or other vapor, particularly products of combustion occurring in an associated fireplace, from the smoke laden air of vapor source which method would comprise providing the improved chimney cover and adjusting the size of the opening between the top of the cover consisting of the roof and the top of the flue as required to provide for the desired flow of the air from the interior of the chimney flue and to provide for the reduction of the desired flow of the air from the exterior of the chimney flue in the form of a down draft. 
     The invention will be described for the purposes of illustration only in connection with certain embodiments; however, it is recognized that those ments and additions on the illustrated embodiments all without departing from the spirit and scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of the chimney cover of the invention; 
     FIG. 2 is a side elevational view of the chimney cover of FIG. 1; with the roof in a partially folded position. 
     FIG. 3 is a side elevational view of the chimney cover of FIG. 1 with the roof shown in the full upright position. 
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     With reference to the drawings, FIG. 1 shows a chimney cover system including a chimney cover 10, installed in a chimney flue 11, comprising a peaked roof 12 in the fully up-right extended position supported by a plurality of support members 14, each support member including an upper arm 16, moveably joined to a lower support arm 18. Each upper arm 16 is moveably attached to the underside of the peaked roof 12, in the preferred embodiment. There are two pairs of support members 14 positioned on opposite sides of a mounting band member 20, such that as the roof 12 is foldably compressed toward the mounting band 20. The support members 14, with a knee action, bend outwardly and away as upper arm 16 and lower support 18 moveably flex at the conventional rivet means provided at. The upper arm 16 has an upper end and a lower end. The lower end being moveably riveted to the upper end of the lower support arm 18 to provide a moveable knee action shown in FIG. 2. The mounting band 20, of generally rectangular construction, comprises a plurality of an arched section 22 sliding bars 24, each having elongated slots 26 for slideably engaging rivet fasteners with prongs 32 securely mounted thereon; mounted within mounting band 20 and fixed by secured thereto, is a dome shaped screen 28 constructed of wire mesh of a size to completely cover conventional chimney flue. The prongs 32, four in number, two placed at the mid point of the arched sections 22, and two at the mid point of slide bars 24, extend outwardly to engage by compression find chimney flue 11. The mounting band 20 may be compressed against the normal outwardly urging force of the band wire mesh construction of the screen for insertion in the flue, where upon the mounting band 20 tightly engages the inner surface of the flue 11. Set screw 36 are provided to lock the prong in secure attachment with the flue 11.